A lot of this depends on oxygen levels as well. The warm water makes the fish much more active..that is as long as the warm weather is not causing dissolved axygen to be less..in which case the fish will conserve energy.
The problem with this is many waters are different in this regard. I've found that in a well oxygenated lakes I've had some amazing success on top water with water temps into the 80's. in fact just the other weekend I managed this beaut on a clodhopper variation made to look like a dragonfly instead of a grasshopper.
The reason I had such great success that day is the wind kept the top layer moving and thusly oxygenated, not to mention pushing low flying insects into the water. If it were not windy, going under water may have been a better option in order to find the layer the fish were holding in, as well as what foods they were eating. I managed quite a few fish and I need to get un lazy to post the trip as I have no points on this profile now
. A good mix of bass and calicos as well as other various sunfish.Below are a few more bass from the same day. Again notice the wind. While no record breakers they were decent bass and all from the top.